CN105473649B

CN105473649B - Polyester film and preparation method thereof

Info

Publication number: CN105473649B
Application number: CN201480046297.3A
Authority: CN
Inventors: 郑斗焕; 白尚铉; 崔城蘭; 曹铉; 宋起相; 金时敏
Original assignee: Kolon Corp
Current assignee: Kolon Corp
Priority date: 2013-06-27
Filing date: 2014-06-27
Publication date: 2019-06-07
Anticipated expiration: 2034-06-27
Also published as: TW201500210A; TWI562890B; CN110028687B; CN110028687A; CN105473649A; JP2016525465A

Abstract

The present invention provides a kind of polyester film and preparation method thereof.More specifically, the present invention provides a kind of polyester film and preparation method thereof, which has excellent optical property, with controllable percent thermal shrinkage, block the migration of oligomer during heating, and there is low haze change rate after the heating, so as to be used for optical applications.

Description

Polyester film and preparation method thereof

Technical field

The present invention relates to a kind of polyester films and preparation method thereof.More particularly it relates to a kind of polyester film and its system Preparation Method, the polyester film have excellent optical property, have controllable percent thermal shrinkage, block oligomer during heating Migration, and there is low haze change rate after the heating, so as to be used for optical applications.

Background technique

Optical film is a kind of film of optical component as display, it is used as the optical material of LCD BLU, or is used as The optical component of the surface protection of various displays (such as LCD, PDP, touch screen etc.).

This optical film needs excellent transparency and visibility, and uses with excellent mechanically and electrically performance Biaxial stretching polyester film is as basilar memebrane.

However, since this biaxial stretching polyester film surface hardness is low, and lack wearability or marresistance, so working as When optical component as various displays, due to the friction of object or contact its surface and be easy to happen damage.In order to keep away Exempt from this damage, is laminated hard conating, and on the surface of film ready for use in order to improve polyester film and the hard painting as basement membrane Adhesiveness between layer, can form priming coat as middle layer.

In terms of there is the quality because of oligomer migration in the polyester film for display.Therefore, it is coated on it In last handling process such as solidification process, ageing process after adhesive etc., when polyester film is exposed to high temperature, oligomer exists Migration in polyester film, to cause polyester film to bleach or crimp due to thermal deformation.In addition, diamond shape trace can be generated, wherein Under the pressure for preparing diamond-shaped pattern table roll used in the cutting process after polyester film, argyle design is formed.When occur in this way Albinism and when diamond shape trace, film roll is contaminated in this process, the optical performance degradation of finished product.

Always strive to prevent the migration of oligomer in polyester film.As low to control by forming laminated film on polyester film The patent document of polymers migration, Japanese Patent Laid-Open No.2007-253511 (on October 4th, 2007) disclose a kind of poly- Ester film has laminated film at least one surface of the film, wherein when heating 60 minutes at 150 DEG C to the film, in layer The average-size for the oligomer particle being precipitated on press mold is 10 μm for area²Hereinafter, and in 100 μm of 100 μ m of view Number of particles is 100 or less in open country.The invention is intended to control oligomer migration, however, cannot block oligomer migration completely. Also, polyester film high temperature ageing simultaneously uses, or uses high heat resistance polymer such as polyethylene glycol phthalate (PEN) Or polyimides (PI).However, film prepares yield deficiency, occurs using polyester film after aging under high temperature Because of the deformation of moisture etc., in the case where high heat resistance polymer, although oligomer migration does not occur, with polyester phase Than manufacturing cost is significantly high, and post-processing is difficult.

Also, other than blocking oligomer migration, touch screen panel panel products are substantially also necessary to ensure that in post-processing Processing performance.Other than ito film, touch screen panel panel products are by three layers of lamination or more of film for example for the resistance to of ITO protection Hotting mask and for hard conating (on its two surfaces coating reduce arch bottom) polyester film come using.Therefore, three Layer or more film percent thermal shrinkage it is different in the case where, there is example because of percent thermal shrinkage difference in last handling process at high temperature The problem such as crimp, to wrinkle, therefore, the quality of product can reduce.

Therefore, process conditions are improved, it is (high with the different percent thermal shrinkages ensured from the process conditions of customer enterprise match Percent thermal shrinkage and low percent thermal shrinkage) it is also essential.

Summary of the invention

Technical problem

It is an object of the present invention to provide a kind of polyester film, which blocks oligomer migration completely.

In addition, it is a further object of the present invention to provide a kind of polyester film, which has high hot property and excellent Aftertreatment performance, and the percent thermal shrinkage in post-processing can be significantly reduced.

In addition, it is a further object of the present invention to provide a kind of optical films including the polyester film.

In addition, the polyester film after the heating can it is a further object of the present invention to provide a kind of preparation method of polyester film Block oligomer migration, while controlling percent thermal shrinkage.

In addition, it is yet another object of the invention to provide a kind of Polyester multilayer membrane, the Polyester multilayer membrane be suitable for ITO technique, For the basement membrane of ITO, and the basement membrane of the hard conating for touch screen.

Technical solution

In a general way, polyester film includes: the polyester base film and priming coat formed by polyester resin, the primary coat Layer is formed by being coated with water dispersed resin composition on one or two surface of the polyester base film, wherein described poly- Ester film meets following formula 1 and 2:

0≤Smd≤1.5 [formula 1]

0≤Std≤1.0 [formula 2]

Wherein, Smd and Std expression the polyester film having a size of 10cm wide and 10cm long is maintained at 150 DEG C 30 minutes it Afterwards according to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement, wherein percent thermal shrinkage (%)=(film before the heat treatment Length-maintained at 150 DEG C 30 minutes caudacoria length)/before the heat treatment film length × 100, Smd indicate film exist Shrinking percentage (%) on longitudinal (MD), Std indicate shrinking percentage (%) of the film on transverse direction (TD).

The polyester film of an exemplary implementation scheme according to the present invention can satisfy following formula 3 and 4:

- 0.2≤Vmd≤0.2 [formula 3]

- 0.2≤Vtd≤0.2 [formula 4]

Wherein, Vmd and Vtd expression the polyester film having a size of 10cm wide and 10cm long is maintained at 150 DEG C 30 minutes it Afterwards according to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement, wherein percent thermal shrinkage (%)=(film before the heat treatment Length-maintained at 150 DEG C 30 minutes caudacoria length)/before the heat treatment film length × 100, Vmd expression be based on The overall with of film, with the deviation (%) of the percent thermal shrinkage of 10 samples of the interval selection of 50cm in the longitudinal direction, Vtd indicates to be based on film Overall with, the deviation (%) of the percent thermal shrinkage of 10 samples selected with the interval of 50cm horizontally.

The polyester film of an exemplary implementation scheme according to the present invention can satisfy following formula 5 to 7:

0≤S (45)≤1.0 [formula 5]

0≤S (135)≤1.0 [formula 6]

| S (135)-S (45) |≤0.2 [formula 7]

Wherein, S (45) and S (135) indicates the polyester film having a size of 10cm wide and 10cm long maintaining 30 points at 150 DEG C According to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement after clock, wherein the percent thermal shrinkage (%)=(in heat treatment The length-of cephacoria maintains the length of 30 minutes caudacorias at 150 DEG C) length × 100, S (45) table of/film before the heat treatment Show the diagonally adjacent shrinking percentage (%) on the 45° angle degree clockwise of the transverse direction (TD) based on film, S (135) expression is based on Diagonally adjacent shrinking percentage (%) in 135 ° of angles clockwise of the transverse direction (TD) of film.

The polyester film of an exemplary implementation scheme according to the present invention can satisfy following formula 8 and 9:

0.1590≤ns [formula 8]

Hf≤Hi × 2.5 [formula 9]

Wherein, ns is surface orientation coefficient, wherein ns={ (refractive index in the longitudinal direction+refractive index) horizontally/2 }- { (refractive index of the thickness of the refractive index of thickness in the longitudinal direction+horizontally)/2 }；And

Hf indicates the mist degree that 30 minutes caudacorias are maintained at 150 DEG C；Hi indicates the mist degree of film before heating.

In the polyester film of an exemplary implementation scheme according to the present invention, the polyester base film may include: substrate Layer, and at least two surface layers being laminated on two surfaces of the basal layer, form the low of the polyester resin on the surface layer Copolymer content can be 0.3-0.6wt%, and diethylene glycol content can be 0.1-1.2wt%.

In the polyester film of an exemplary implementation scheme according to the present invention, the polyester base film can pass through the base The coextrusion on bottom and surface layer is formed, and has the inherent viscosity for meeting following formula 10:

1 Ns/Nc≤1.2 < [formula 10]

Wherein, Ns indicates to form the inherent viscosity of the polyester resin on the surface layer；Nc indicates to form the poly- of the basal layer The inherent viscosity of ester resin.

In the polyester film of an exemplary implementation scheme according to the present invention, in the polyester base film, the base is formed The inherent viscosity of the polyester resin of bottom be 0.5 to 1.0, formed the polyester resin on the surface layer inherent viscosity be 0.6 to 1.0。

In the polyester film of an exemplary implementation scheme according to the present invention, the Tg of the priming coat can for 60 DEG C with On, swelling ratio can be for 30% hereinafter, gel fraction can be 95% or more, and density can be 1.3-1.4.

The polyester film of an exemplary implementation scheme according to the present invention is according to the haze change rate (Δ of following formula 11 H can be) 0.1% or less:

Δ H (%)=Hf-Hi [formula 11]

Wherein, Hf indicates the mist degree that 60 minutes caudacorias are maintained at 150 DEG C；Hi indicates the mist degree of film before heating.

In the polyester film of an exemplary implementation scheme according to the present invention, the water dispersed resin composition be can wrap Containing by (A) and being copolymerized the unsaturated monomer of the free redical polymerization containing glycidyl the acrylic resin that is formed And (B) water dispersible polyester resinoid is formed by adhesive resin.(A) pass through make containing glycidyl can be free The unsaturated monomer of base polymerization is copolymerized and the solid between the acrylic resin and (B) the water dispersible polyester resinoid of formation Content weight ratio can be (A)/(B)=20-80/80-20.

In the polyester film of an exemplary implementation scheme according to the present invention, the bonding of the water dispersed resin composition The solid content of agent resin can be 0.5-10wt%.

In the polyester film of an exemplary implementation scheme according to the present invention, the water dispersed resin composition can be with Include organic silicon wetting agent.

In the polyester film of an exemplary implementation scheme according to the present invention, the water dispersible polyester resinoid can lead to Crossing makes to include that the dicarboxylic acid component of sulfonate alkali metal salt compound is copolymerized with the diol component for including diethylene glycol (DEG) and is formed.

In the polyester film of an exemplary implementation scheme according to the present invention, the water dispersible polyester resinoid be can wrap The diethylene glycol (DEG) of 20-80mol% containing whole diol components.

In the polyester film of an exemplary implementation scheme according to the present invention, the water dispersible polyester resinoid be can wrap The sulfonate alkali metal salt compound of 6-20mol% containing whole acid constituents.

In the polyester film of an exemplary implementation scheme according to the present invention, the acrylic resin be may include entirely The unsaturated monomer of the free redical polymerization containing glycidyl of the 20-80mol% of portion's monomer component, it is single as copolymerization Body.

In the polyester film of an exemplary implementation scheme according to the present invention, the polyester base film can be to be poly- to benzene two Formic acid glycol ester film.

In the polyester film of an exemplary implementation scheme according to the present invention, the thickness of the polyester base film can be 25-250μm。

In the polyester film of an exemplary implementation scheme according to the present invention, the dry coating thickness of the priming coat can Think 20-150nm.

In the polyester film of an exemplary implementation scheme according to the present invention, the polyester base film may include 70- The basal layer of 90wt% and the surface layer of 10-30wt%.

The surface roughness (Ra) of the polyester film of an exemplary implementation scheme according to the present invention can be 10nm or less.

In the polyester film of an exemplary implementation scheme according to the present invention, the surface layer may include 100ppm or less Inorganic particulate.

In the polyester film of an exemplary implementation scheme according to the present invention, the average grain diameter of the inorganic particulate can be with Less than 3 μm.

In the polyester film of an exemplary implementation scheme according to the present invention, the inorganic particulate can be for selected from dioxy Any one or two or more mixture in SiClx, zeolite and kaolin.

In terms of another total, a kind of optical film, which has, is selected from hard conating, adhesive layer, optical diffusion layer, ITO layer and printing layer In any one or more functional coating be formed on above-mentioned polyester film.

In terms of another total, the method for preparing polyester film includes: the polyester of a) preparation simple tension on longitudinal direction (MD) Basement membrane；

B) coating has oligomer retardation capability on one or two surface of the polyester base film of the simple tension Water dispersed resin composition, to form priming coat；

C) it will be formed with polyester base film biaxial tension on transverse direction (TD) of the simple tension of the priming coat thereon；And

D) thermal finalization is carried out to the film of the biaxial tension, and right on MD in the range of meeting following formula 12 The film relaxes:

1.1≤relaxation rate (%)≤2.5 [formula 12]

Wherein, the relaxation rate (%)=(relaxation processes section inner membrance movement speed-relaxation processes section cephacoria shifting Dynamic speed)/in movement speed × 100 of relaxation processes section cephacoria.

In the method for preparing polyester film of an exemplary implementation scheme according to the present invention, in step d) on MD Relaxation can carry out within the temperature range of meeting following formula 13:

Draft temperature (DEG C)≤relaxation temperature (DEG C) < heat setting temperature (DEG C) [formula 13]

In the method for preparing polyester film of an exemplary implementation scheme according to the present invention, the water dispersed resin group Close object may include by (A) pass through make the free redical polymerization containing glycidyl unsaturated monomer copolymerization and formed third Olefin(e) acid resinoid and (B) water dispersible polyester resinoid are formed by adhesive resin, and (A) by making containing shrink The unsaturated monomer of glyceryl free redical polymerization is copolymerized and the acrylic resin formed and (B) the water dispersible polyester class Solid content weight ratio between resin is (A)/(B)=20-80/80-20.

In the method for preparing polyester film of an exemplary implementation scheme according to the present invention, the heat of the polyester film is received Shrinkage (%) can satisfy following formula 1 to 4:

0≤Smd≤1.0 [formula 1]

0≤Std≤0.5 [formula 2]

- 0.2≤Vmd≤0.2 [formula 3]

- 0.2≤Vtd≤0.2 [formula 4]

Wherein, Smd, Std, Vmd and Vtd expression maintains the polyester film having a size of 10cm wide and 10cm long at 150 DEG C According to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement after 30 minutes, wherein the percent thermal shrinkage (%)=(in Re Chu The length-of the cephacoria of reason maintains the length of 30 minutes caudacorias at 150 DEG C) length × 100, Smd of/film before the heat treatment Indicate shrinking percentage (%) of the film on longitudinal direction (MD), Std indicates shrinking percentage (%) of the film on transverse direction (TD), and Vmd expression is based on The overall with of film, the deviation (%) of percent thermal shrinkage of 10 samples selected with the interval of 50cm on MD, Vtd are indicated based on film Overall with, the deviation (%) of percent thermal shrinkage of 10 samples selected with the interval of 50cm on TD.

In the method for preparing polyester film of an exemplary implementation scheme according to the present invention, the polyester film can expire The formula 5 to 7 in foot face:

0≤S (45)≤1.0 [formula 5]

0≤S (135)≤1.0 [formula 6]

| S (135)-S (45) |≤0.2 [formula 7]

Wherein, S (45) and S (135) indicates the polyester film having a size of 10cm wide and 10cm long maintaining 30 points at 150 DEG C According to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement after clock, wherein the percent thermal shrinkage (%)=(in heat treatment The length-of cephacoria maintains the length of 30 minutes caudacorias at 150 DEG C) length × 100 of/film before the heat treatment；S (45) table Show the diagonally adjacent shrinking percentage (%) on the 45° angle degree clockwise of the transverse direction (TD) based on film；S (135) expression is based on Diagonally adjacent shrinking percentage (%) in 135 ° of angles clockwise of the transverse direction (TD) of film.

In the method for preparing polyester film of an exemplary implementation scheme according to the present invention, the Tg of the priming coat can Think 60 DEG C or more, swelling ratio can be for 30% hereinafter, gel fraction can be 95% or more, and density can be 1.3-1.4.

In the method for preparing polyester film of an exemplary implementation scheme according to the present invention, the polyester film is under The haze change rate (Δ H) of the formula 11 in face can be 0.1% or less:

Δ H (%)=Hf-Hi [formula 11]

In terms of another total, the method for preparing polyester film includes:

A) by the diethylene glycol (DEG) of the oligomer comprising the 0.3-0.6wt% containing the polyester resin and 0.1-1.2wt% The skin combined object of first polyester resin, and for the second polyester resin melting extrusion and coextrusion of basal layer, have full The inherent viscosity of the formula 10 in foot face:

1 Ns/Nc≤1.2 < [formula 10]

Wherein, Ns indicates to form the inherent viscosity of the polyester resin on the surface layer；Nc indicates to form the poly- of the basal layer The inherent viscosity of ester resin；

B) uniaxial or biaxial stretching is carried out to the thin slice of the coextrusion to prepare film；And

C) thermal finalization is carried out to the film of the stretching, in the range of meeting following formula 14 on TD to the film into Row relaxation:

2≤TDr (%)≤11.5 [formula 14]

Wherein, TDr indicates the relaxation rate on TD, wherein the relaxation rate (%)={ (in the cephacoria of relaxation processes section Minimum widith length of the maximum width length-in relaxation processes section inner membrance on TD on TD)/in the cephacoria of relaxation processes section Maximum width length × 100.

Skin combined object in step a) may include 100ppm inorganic particulate below.

In addition, the average grain diameter of the inorganic particulate can be less than 3 μm.

The surface roughness (Ra) of the polyester film can be 10nm hereinafter, percent thermal shrinkage can satisfy following formula 1 With 2, surface orientation coefficient (ns) can satisfy following formula 8, and the mist degree after the film is maintained 30 minutes at 150 DEG C can To meet following formula 9:

0≤Smd≤1.5 [formula 1]

0≤Std≤1.0 [formula 2]

0.1590≤ns [formula 8]

Hf≤Hi × 2.5 [formula 9]

Wherein, Smd and Std expression the polyester film having a size of 10cm wide and 10cm long is maintained at 150 DEG C 30 minutes it Afterwards according to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement, wherein percent thermal shrinkage (%)=(film before the heat treatment Length-maintained at 150 DEG C 30 minutes caudacoria length)/before the heat treatment film length × 100, Smd indicate film exist Shrinking percentage (%) on MD, Std indicate shrinking percentage (%) of the film on TD；

Ns is surface orientation coefficient, wherein ns={ (refractive index in the longitudinal direction+refractive index) horizontally/2 }-( The refractive index of the thickness of the refractive index of longitudinal thickness+horizontally)/2；And

Hf indicates that the mist degree that 30 minutes caudacorias are maintained at 150 DEG C, Hi indicate the mist degree of film before heating.

In addition, the relaxation on MD can be in the range for meeting following formula 15 when being relaxed in step c) Interior progress, while relaxing on TD:

0.3≤MDr (%)≤2.5 [formula 15]

Wherein, MDr indicates the relaxation rate on MD, wherein the relaxation rate (%)=(in the shifting of relaxation processes section inner membrance Movement speed of the dynamic speed-in the cephacoria of relaxation processes section)/relaxation processes section cephacoria movement speed × 100.

Beneficial effect

Polyester film according to the present invention has the effect of under the high temperature conditions retardance oligomer migration completely.

In addition, polyester film according to the present invention has suitable for the heat-resistant film etc. for ITO protection in touch-screen film Optical physics performance, and the percent thermal shrinkage of the overall with by control film, it is easy to ensure that aft-loaded airfoil performance, especially at three layers Processing performance in the lamination process of above film such as ito film, ITO heat-resisting protective film, low interference figure polyester film etc..

Specific embodiment

Hereinafter, it will be described in embodiment of the present invention.

Herein, oligomer refers to the dimer, trimer, tetramer etc. that weight average molecular weight is about 500-10000.

The polyester film of an embodiment according to the present invention includes: the polyester base film formed by polyester resin and bottom Coating, the priming coat on one or two surface of the polyester base film by being coated with the moisture with oligomer retardation capability Scattered resin combination is formed, and has the percent thermal shrinkage (%) for meeting following formula 1 to 4:

0≤Smd≤1.0 [formula 1]

0≤Std≤0.5 [formula 2]

- 0.2≤Vmd≤0.2 [formula 3]

- 0.2≤Vtd≤0.2 [formula 4]

The polyester film of an exemplary implementation scheme according to the present invention can satisfy formula 1 and 2 or formula 3 and 4, Or equation 1 above is to 4 all formula 1 to 4.The physical property condition can be combined with other conditions.

Percent thermal shrinkage (%) of the film on MD can be 0-1.5%, preferably 0.2-1.5%, more preferably 0-1.0%. When percent thermal shrinkage (%) of the film on MD is less than 0%, film can expand, to increase the possibility for causing curling in post-processing Property, when be greater than 1.5% when, the shrinkage in post-processing on MD can be improved, thus also will increase cause curling can It can property.It is highly preferred that the percent thermal shrinkage on MD can be 0-0.9%.

In addition, the percent thermal shrinkage (%) on TD can be 0-1.0%, preferably 0-0.5%.When the thermal contraction on TD When rate (%) is less than 0%, expansion of the film on TD can be caused, when being greater than 1.0%, improve the contraction in post-processing on TD Performance, to be difficult to control curling.It is highly preferred that the percent thermal shrinkage on TD is 0-0.4%.

In addition, polyester film, which may include, meets following those of formula 5 to 7:

0≤S (45)≤1.0 [formula 5]

0≤S (135)≤1.0 [formula 6]

| S (135)-S (45) |≤0.2 [formula 7]

Wherein, S (45) and S (135) indicates the polyester film having a size of 10cm wide and 10cm long maintaining 30 points at 150 DEG C According to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement after clock, wherein the percent thermal shrinkage (%)=(in heat treatment The length-of cephacoria maintains the length of 30 minutes caudacorias at 150 DEG C) length × 100 of/film before the heat treatment.In addition, S (45) the diagonally adjacent shrinking percentage (%) on the 45° angle degree clockwise of the transverse direction (TD) based on film, S (135) table are indicated Show the diagonally adjacent shrinking percentage (%) in 135 ° of angles clockwise of the transverse direction (TD) based on film.

In the present invention, polyester film can adjust percent thermal shrinkage in the diagonal directions within the above range, to make The migration retardation capability for obtaining oligomer under the high temperature conditions maximizes.Furthermore, it is possible to realize the Typical physical for improving polyester film Effect of the energy (including its optical property).Film is on the 45° angle degree clockwise based on TD and film is based on the clockwise of TD The percent thermal shrinkage of (these angles are in the diagonally adjacent of polyester film) can be preferably 0-1.0% in 135 ° of angles.Meanwhile The absolute value of the difference of two diagonally adjacent percent thermal shrinkages can be preferably 0.2% or less.When percent thermal shrinkage difference it is exhausted When being greater than 0.2% to value, contraction balance in the diagonal directions can be broken, so as to cause the curling of distorted form.

In addition, the deviation of the percent thermal shrinkage of the overall with of film be ± 0.2% in the range of, it can be ensured that percent thermal shrinkage it is equal Even property, and can easily control curling.

0.1590≤ns [formula 8]

Hf≤Hi × 2.5 [formula 9]

The surface orientation coefficient of the polyester film of an exemplary implementation scheme according to the present invention is preferably 0.1590, more preferably For 0.1590-0.1610.When surface orientation coefficient is less than 0.1590, the surface texture of film is not fine and close, therefore can be easy to happen low The surface migration of polymers.

Mist degree is for determining the migration of oligomer under the high temperature conditions, when it is when except the range of equation 9 above, table Show that oligomer seriously migrates, therefore mist degree reduces.Within the scope of mist degree above, aft-loaded airfoil performance is not significantly affected, therefore, is gathered Ester film has the physical property for being suitable as optical film.

The polyester film of an exemplary implementation scheme according to the present invention may include polyester base film, the polyester base film packet It includes: basal layer, and at least two surface layers being laminated on two surfaces of the basal layer.Herein, the surface layer is formed The oligomer of polyester resin can be 0.3-0.6wt%, and diethylene glycol content can be 0.1-1.2wt%.

The polyester base film can by include basal layer, and be laminated on two surfaces of the basal layer two layers with Three layers or more compositions of upper epidermis, and can be formed by being coextruded.

In order to improve when being coextruded basal layer and processing performance when surface layer, following formula 10 is preferably satisfied:

1 Ns/Nc≤1.2 < [formula 10]

When the inherent viscosity ratio between surface layer and basal layer is greater than 1.2, interfacial instability occurs during coextrusion The problem of, so that multilayered structure is not formed, it is therefore preferable that meeting range above, it is highly preferred that being 1.0 to 1.05, with effective Ground improves processing performance.

The overall thickness of polyester base film is preferably 25 to 250 μm, it is highly preferred that 50 to 188 μm more effective.When thickness is less than 25 μm when, can not achieve the mechanical and physical performance suitable for optical film, when thickness be greater than 250 μm when, the thickness of film becomes too thick, To be not suitable for keeping display thinning.

Moreover it is preferred that the content of basal layer is 70 to 90wt% based on whole films, the content on surface layer be 10 to 30wt%, it is highly preferred that the content of basal layer is 70 to 80wt% based on whole films, the content on surface layer is 20 to 30wt%, with There is excellent interface stability and excellent oligomer blockage effect during coextrusion, to work.

Preferably, the basal layer formed by polyester resin is only made of polyethylene terephthalate (PET) resin.This Place, the inherent viscosity of the pet resin used is preferably 0.5 to 1.0, it is highly preferred that inherent viscosity is 0.60 to 0.80, to work.When the inherent viscosity of the pet resin of basal layer is lower than 0.5, Its heat resistance can reduce, when being greater than 1.0, it is not easy to feedstock processing is carried out, to reduce processing performance.

Based on total film weight, the surface layer formed by being coextruded at least two layers on two surfaces of polyester substrate Oligomer can be 0.3 to 0.6wt%, more preferably 0.4 to 0.6wt%, diethylene glycol (DEG) (DEG) content can be 0.1 To 1.1wt%, more preferably 0.7 to 1.1wt%.When the oligomer of the polyester resin on surface layer and the content of diethylene glycol (DEG) are higher than above Range when, the haze value of initial film increases, and when heat treatment process, haze change rate is sharply increased, so as to cause can not achieve The problem of can be used for the optical property of optical film.

In addition, the oligomer of the polyester resin in order to make surface layer and the content of diethylene glycol (DEG) are in range above, resin can To be prepared by synthetic method as known in the art, notably, however, resin is prepared by solid phase can be effective Reduce the content of oligomer and diethylene glycol (DEG).

Moreover it is preferred that the inherent viscosity of the polyester resin on surface layer is 0.6 to 1.0, it is highly preferred that 0.65 to 0.85 more Effectively.When the inherent viscosity of the pet resin on surface layer is less than 0.6, its heat resistance can be reduced, when When greater than 1.0, it can be not easy to carry out Raw material processing, to reduce processing performance.

The polyester film of an exemplary implementation scheme according to the present invention may include that Tg is 60 DEG C or more, and swelling ratio is 30% hereinafter, gel fraction is 95% or more, and density is the priming coat of 1.3-1.4.When preparing polyester film, which can be with The migration of oligomer is controlled, while reducing percent thermal shrinkage.

In addition, relaxing in predefined conditions when preparing film in heat setting step, to meet at 150 DEG C Haze change rate before and after heating 60 minutes is 0.1% physical property below, and meets in the present invention and to realize Film percent thermal shrinkage.

Furthermore, it is possible to determine, the film that oligomer migration degree is met the above range does not show diamond shape trace and albefaction.

That is, meeting physical property such as Tg in priming coat is 60 DEG C or more, swelling ratio is 30% hereinafter, gel fraction is 95% or more, density is in 1.3 or more range, priming coat can satisfy the haze change rate (Δ according to following formula 11 H) it is 0.1% physical property below:

Δ H (%)=Hf-Hi [formula 11]

It is 60 DEG C or more, more specifically 60 DEG C or more and does not have specifically, meets physical property such as Tg in priming coat Have a upper limit, swelling ratio is 30% hereinafter, more specifically 0% to 30%, and gel fraction is 95% or more, more specifically 95 to 100%, in the range of density is 1.3 or more, more specifically 1.3 to 1.4, it may be determined that even if in the close structure of coating The mobility of degree and priming coat reduces, and in the case where applying higher temperature and pressure to it, the oligomer in polyester film It will not move on its surface.

In the polyester film of an exemplary implementation scheme according to the present invention, priming coat can have oligomeric by coating The water dispersed resin composition of object retardation capability is formed.

As the water dispersed resin composition for being used to form priming coat, can be used comprising by making containing glycidyl Free redical polymerization unsaturated monomer copolymerization and formed acrylic resin and water dispersible polyester resinoid water dispersion Resin combination.

As an embodiment, in the water dispersed resin composition, (A), which passes through, to be made to can oneself containing glycidyl By the unsaturated monomer copolymerization of base polymerization, the solid between the acrylic resin formed and (B) water dispersible polyester resinoid contains Measuring weight ratio can be (A)/(B)=20-80/80-20.More specifically, the weight ratio of 40-60/60-40 can be used.As (B) When the solid content of water dispersible polyester resinoid is less than 20wt%, and (A) by making the free redical containing glycidyl When the solid content of acrylic resin that the unsaturated monomer of polymerization is copolymerized and is formed is greater than 80wt%, the particle ruler of emulsion Therefore very little increase can generate color spot, and reduce with the adhesiveness of polyester base film and transparency online when coating.When (B) moisture The solid content for dissipating polyester resin is greater than 80wt%, and (A) by making the free redical polymerization containing glycidyl Unsaturated monomer copolymerization and formed acrylic resin solid content be less than 20wt% when, can not achieve sufficient oligomer Blockage effect.

Water dispersed resin composition of the invention can by by (B) water dispersible polyester resinoid and (A) by make containing The acrylic resin that the unsaturated monomer of the free redical polymerization of glycidyl is copolymerized and is formed is mixed and is formed Adhesive resin is mixed to prepare with water, can also be in the aqueous dispersions of (B) water dispersible polyester resinoid, by that will contain There is the unsaturated monomer of the free redical polymerization of glycidyl individually to be polymerize to prepare, or with can with containing shrink It is prepared by the polymerization of unsaturated monomers of the free redical polymerization of the unsaturated monomer copolymerization of glyceryl free redical polymerization.This Place, can be used surfactant or polymerization initiator.As long as surfactant and polymerization initiator are commonly used in emulsion polymerization In, it can using them without limiting.Specifically, for example, it is living that anionic surface can be used as surfactant Property agent, nonionic surfactant or non-reactive surfactant, also can be used their combination.Cause as polymerization Nitrogen compound (for radical polymerization initiator) such as peroxide type initiators or azodiisobutyronitrile can be used in agent.

As needed, water-dispersed composition of the invention can also include defoaming agent, wetting agent, surfactant, thickening Agent, plasticizer, antioxidant, UV absorbent, preservative, crosslinking agent etc..

In water-dispersed composition of the invention, (B) water dispersible polyester resinoid can be by making to include sulfonate alkali metal The dicarboxylic acid component of salt compound is copolymerized to be formed with the diol component for including diethylene glycol (DEG).

More specifically, aromatic dicarboxylic acid and sulfonate alkali metal salt compound can be used as dicarboxylic acid component, wherein It may include the sulfonate alkali metal salt compound of the 6-20mol% of whole acid constituents.

As dicarboxylic acid component, aromatic dicarboxylic acid such as phthalic acid, terephthalic acid (TPA), dimethyl can be used to benzene Dioctyl phthalate, M-phthalic acid, dimethyl M-phthalic acid, 2,5- dimethyl terephthalic acid, 2,6- naphthalene dicarboxylic acids or biphenyl two Carboxylic acid；Aliphatic dicarboxylic acid such as adipic acid or decanedioic acid；Alicyclic dicarboxylic acid such as cyclohexyl dicarboxylic acid etc..

As sulfonate alkali metal salt compound, specifically, it is, for example, possible to use such as sulfonic group terephthalic acid (TPA)s, 5- The alkali metal salt of sulfonic group M-phthalic acid, 4- sulfonic group M-phthalic acid or 4- sulfonic group naphthoic acid -2,7- dicarboxylic acids etc., and It is preferable to use 6-20mol%.When being used below 6mol%, the jitter time of resin in water extends, and dispersibility reduces, When using 20mol% is higher than, water resistance can be deteriorated.

As diol component, diethylene glycol (DEG), the alicyclic diol with 2-8 carbon atom or 6-12 carbon atom can be used Deng.Specifically, it is, for example, possible to use ethylene glycol, 1,3-PD, 1,2-PD, neopentyl glycol, 1,4-butanediol, 1, 4- cyclohexanedimethanol, 1,3-CHDM, 1,2-CHDM, 1,6- hexylene glycol, terephthalyl alcohol (P- Xylene glycol), triethylene-glycol etc..Herein, it is preferable that comprising whole diol components 20 Dao 80mol% it is two sweet Alcohol.

Preferably, the number-average molecular weight of (B) water dispersible polyester resinoid is 1000-50000, it is highly preferred that the equal molecule of number Amount is 2000-30000.When number-average molecular weight is less than 1000, oligomer blockage effect can be unobvious, when the equal molecular wt of number is big When 50000, it is difficult to carry out water dispersion.

For using (B) water dispersible polyester resinoid, it can be by being heated to 50 to 90 DEG C while stirring come equably Be dispersed in water or the liquid solvent containing water in.Preferably, in order to evenly dispersed, the solid of the aqueous dispersions thus prepared contains Measuring concentration is 30wt% hereinafter, more preferably 10-30wt%.Aqueous solvent can be alcohol such as methanol, ethyl alcohol or propyl alcohol, polyhydroxy Base alcohol such as ethylene glycol, propylene glycol, diethylene glycol (DEG), dipropylene glycol or glycerine etc..

Next, (A) will be described and being copolymerized the unsaturated monomer of the free redical polymerization containing glycidyl The acrylic resin of formation.

(A) acrylic compounds formed and being copolymerized the unsaturated monomer of the free redical polymerization containing glycidyl Resin, can be by will containing the unsaturated monomer of the free redical polymerization of glycidyl, or can with containing shrink The homopolymer of the unsaturated monomer of another free redical polymerization of the unsaturated monomer copolymerization of glyceryl free redical polymerization is total Poly- and formation resin.

Acrylic resin may include the 20-80mol% of whole monomer components containing glycidyl can be free The unsaturated monomer of base polymerization, as comonomer.The unsaturated monomer of free redical polymerization containing glycidyl passes through Cross-linking reaction improves the coating strength of priming coat, and improves crosslink density, to block oligomer migration.Specifically, example Such as, it is sweet that glycidol ether such as glycidyl acrylate, glycidyl methacrylate or allyl glycidyl can be used Oily ether etc..

The free redical polymerization that can be copolymerized with the unsaturated monomer of the free redical polymerization containing glycidyl is not Being saturated monomer can be vinyl esters, esters of unsaturated carboxylic acids, unsaturated carboxylic acid amide, unsaturated nitrile, unsaturated carboxylic acid, allyl Compound, nitrogenous vinyl monomer, alkyl-vinyl base monomer, vinyl silane compound etc..As vinyl esters, can be used Vinyl propionate, stearic acid vinyl ester, vinyl chloride etc..As esters of unsaturated carboxylic acids, methyl acrylate, acrylic acid second can be used Ester, butyl acrylate, acrylic acid-2-ethyl caproite, ethyl methacrylate, butyl methacrylate, butyl maleate, Malaysia Misery ester, fumaric acid butyl ester, fumaric acid monooctyl ester, hydroxyethyl methacrylate, hydroxy-ethyl acrylate, hydroxy propyl methacrylate, Hydroxypropyl acrylate etc..As unsaturated carboxylic acid amide, acrylamide, Methacrylamide, methylol acryloyl can be used Amine, butoxymethylol acrylamide etc..As unsaturated nitrile, acrylonitrile etc. can be used.As unsaturated carboxylic acid, can make With acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleate, fumarate, itaconate etc..As alkene Allyl acetate, allyl methacrylate, allyl acrylate, allyl itaconates, clothing health can be used in compound Diallyl phthalate etc..As nitrogenous vinyl monomer, vinylpyridine, vinyl imidazole etc. can be used.As alkyl-vinyl Ethylene, propylene, hexene, octene, styrene, vinyltoluene, butadiene etc. can be used in base monomer.As vinyl silanes Dimethylvinylmethoxysiiane, Vinyldimethylethoxysilane, methyl ethylene dimethoxy can be used in compound Base silane, methyl vinyl diethoxysilane, γ-methacryloxypropyl trimethoxy silane, γ-methacryl Oxygroup propyldimethoxy-silane etc..

Preferably, the water dispersed resin composition of an embodiment according to the present invention is (A) by making containing shrink The unsaturated monomer of glyceryl free redical polymerization is copolymerized and the acrylic resin and (B) water dispersible polyester resinoid of formation Solid content be 0.5-10wt% water dispersion or water-based composition.More specifically, water dispersed resin composition may include (A) that solid content is 0.5-10wt% is and being copolymerized the unsaturated monomer of the free redical polymerization containing glycidyl The acrylic resin of formation and (B) water dispersible polyester resinoid, and remaining is water, also includes additive example as needed Such as wetting agent or dispersing agent.Wetting agent is for improving coating, specifically, it is, for example, possible to use modified organic silicon profits TEGO WET 250, BYK 348 of BYK CHEMIE of humectant such as Q2-5212, ENBODIC of Dow Corning etc., still It is without being limited thereto.Preferably, using the wetting agent of 0.1-0.5wt%, in the range, required coating performance may be implemented and change It is kind.

The dry coating thickness of priming coat in the present invention can be 20-150nm.When dry coating thickness is less than 20nm When, it cannot sufficiently realize oligomer retardation capability, when being greater than 150nm, occur applying spot, and be very likely to after in film roll and draw Blocking is played, i.e., priming coat is adhered to one another.

Water dispersed resin composition in the present invention can be by applying in polyester film preparation process in line painting method Cloth.That is, when preparing polyester base film, water dispersed resin composition can before the stretching, or the succeeding stretch after first stretch Before, by being coated in line painting method, then stretches, the succeeding stretch and heat setting process during, pass through heating and steam Shampoo is to form priming coat.To coating method, there is no limit as long as any coating method as known in the art.

More specifically, the method for preparing polyester film of the invention includes:

A) polyester base film of preparation simple tension on longitudinal direction (MD)；

1.1≤relaxation rate (%)≤2.5 [formula 12]

Wherein, relaxation rate (%)=(relaxation processes section inner membrance movement speed-relaxation processes section cephacoria movement Speed)/relaxation processes section cephacoria movement speed × 100.

In step d) of the invention, carried out within the temperature range of meeting following formula 13 in the relaxation on MD:

In the present invention, after as described above stretch, thermal finalization and relaxation are carried out on MD, relaxation is meeting formula It is carried out under conditions of 9 and 10, therefore oligomer does not migrate under the high temperature conditions, and film is not shunk, thus after being prepared with and being conducive to The film of processing.

More specifically, in the method for preparing polyester film of the invention, step a) be polyester slice is added to extruder, and And melting extrusion, then they are quenched with curtain coating drum (casting drum) and is solidified to prepare polyester sheet, thereafter, Simple tension is carried out to thin slice on MD at 80-100 DEG C.Herein, it is preferable that stretch ratio is 2-4 times.

Step b) is the process that water dispersed resin composition is coated on the polyester base film of simple tension, and coating uses ability Method known to field technique personnel carries out.

Step c) is will to be formed with polyester base film biaxial tension on TD of priming coat thereon, it is preferable that at 110-150 DEG C Under film is stretched with 2-4 times of ratio.

Step d) is to carry out thermal finalization and relaxation, and can carry out in stenter.Heat setting temperature can be 200- 240 DEG C, the temperature in relaxation preferably carries out in the range of meeting following formula 13:

MD relaxation equipment can be used on longitudinal direction (MD) in relaxation, and with the different paths on thin slice on transverse direction (TD) Come carry out.MD relaxation equipment can by be heat-treated after section whole 9 rails between manufacture the speed difference of about 1.1-2.5% come Control the then shrinkage on MD.Speed difference can be preferably 1.2-2.0%, more preferably 1.25-2.0%.According to MD relaxation proportion adjustment, under conditions of maintenance 30 minutes at 150 DEG C in the percent thermal shrinkage on MD in the range of 0-1.0%, More preferably in the range of 0.3-0.9%.In addition, under the above conditions in the percent thermal shrinkage on TD in the range of 0-0.5%, More preferable 0.0-0.4%.Moreover it is preferred that the deviation of the percent thermal shrinkage of the overall with based on home roll is MD/TD in ± 0.2%.

Surface layer in the present invention may include inorganic particulate, it is preferable that the initial haze of film meets the model less than 1.5% It encloses.Moreover it is preferred that the surface roughness of film is 10nm or less.When surface roughness is greater than 10nm, it can generate and be coated with firmly The Smoothing Problem of finished product afterwards.

More specifically, it is preferable to use particle of 100ppm or less the average grain diameter less than 3 μm.As inorganic particulate, it to be used for film In any particle such as silica, zeolite or kaolin be ok.Such inorganic particulate is appeared in by drawing process The surface of film, so as to improve the sliding capability and coiling performance of film.

If particle size be greater than 3 μm, even if particle content be 100ppm situation lower film below transparency can Deterioration, in addition, surface roughness (Ra) is 10nm or more, that is, slickness deterioration, accordingly, it is difficult to film is used for optical applications, it is special It is not touch screen.

In addition, if particle content is 100ppm or more, the transparency of film is reduced, and therefore, film is not suitable for touch screen. In addition, if mist degree is 1.5% or more, when being used for optical applications or touch screen, transparency is quickly reduced, and translucency is significantly bad Change, be difficult to determine defect by naked eyes in BLU evaluation, to be difficult to be used as optical applications.

Although the preparation of the Polyester multilayer membrane including basal layer and superficial layer of the invention there is no limit, film can by Melting extrusion is carried out at least two melt extruders, is then cast, and carries out biaxial tension to obtain.More specifically, polyester It is squeezed out in an extruder, while polyester and additive such as inorganic particulate such as silica, kaolin or zeolite are another Melting extrusion in one extruder, thereafter, various fusant converge in feed module to be successively coextruded, be cast, cooled down, Then biaxial tension.

In one embodiment, the method for preparing polyester film may include:

A) by the diethylene glycol (DEG) of the oligomer comprising the 0.3-0.6wt% containing the polyester resin and 0.1-1.2wt% The skin combined object of first polyester resin, and for the progress melting extrusion of the second polyester resin and coextrusion of basal layer, tool There is the inherent viscosity for meeting following formula 10:

1 Ns/Nc≤1.2 < [formula 10]

C) thermal finalization is carried out to the film of the stretching, and in the range of meeting following formula 14 on TD to described Film relaxes:

2≤TDr (%)≤11.5 [formula 14]

In the present invention, after as described above stretch, thermal finalization and relaxation on MD are carried out, relaxation is public in satisfaction It is carried out under conditions of formula 6, therefore oligomer does not migrate under the high temperature conditions, and film is not shunk, so that preparation is conducive to post-processing Film.

More specifically, step a) is the polyester that will form basal layer and surface layer in the method for preparing polyester of the invention Then resin coextrusion is quenched with curtain coating drum and is solidified to prepare polyester sheet, it is preferable that made in surface layer and basal layer Polyester resin has the inherent viscosity for meeting following formula 10:

1 Ns/Nc≤1.2 < [formula 10]

Next, step b) is to carry out the thin slice of coextrusion to stretch to be prepared as film, stretch with it is one-way or bi-directional into Row, preferably progress biaxial tension.In the case where biaxial tension, simple tension is carried out at 80-100 DEG C on MD, wherein drawing The ratio of stretching is preferably 2-4 times.Next, as the technique for carrying out biaxial tension on TD, preferably with 2-4 at 110-150 DEG C Ratio again stretches the film.

Step c) is to carry out thermal finalization and relaxation, while step c) can be carried out in stenter.Heat setting temperature can be with It is 200-240 DEG C, the relaxation rate on TD meets following formula 14, to control percent thermal shrinkage:

2≤TDr (%)≤11.5 [formula 14]

Wherein, TDr indicates the relaxation rate on TD, wherein the relaxation rate (%)={ (in the cephacoria of relaxation processes section Minimum widith length of the maximum width length-film in relaxation processes section on TD on TD)/in the cephacoria of relaxation processes section Maximum width length × 100.

In addition, if needing, while being relaxed on TD, can be carried out in the range of meeting following formula 15 Relaxation on MD:

0.3≤MDr (%)≤2.5 [formula 15]

Receipts by relaxing in the range of meeting formula 14 and 15, after film is maintained 30 minutes at 150 DEG C Shrinkage can satisfy formula 1 and 2.

Hard conating, adhesive layer, optical diffusion layer, ITO layer and printing layer can be formed on the top of polyester film of the invention Deng, even if in the case where heating after forming this functional coating oligomer migration can also be blocked to maintain optical property, Therefore, polyester film of the invention is suitable for optical film.

Hereinafter, more detailed description of the invention will be provided by embodiment, however, the present invention is not limited to following implementations Example.

Pass through following measurement method physical properties.

1) percent thermal shrinkage

Film is cut into the standard size of 10cm wide and 10cm long, is then being maintained 150 according to JIS C-2318 measurement DEG C hot-air oven in place 30 minutes after change in size.However, the overall with of film volume is measured with the interval 50cm, It is measured respectively in 45 ° of MD, TD and TD and 135 ° of change in size clockwise.

Percent thermal shrinkage (%)=(length that the length-of film maintains 30 minutes caudacorias at 150 DEG C before the heat treatment)/ Length × 100 of film before the heat treatment.

2) inherent viscosity

0.4gPET particle (sample) is added to the phenol and 1 of 100ml, 1,2,2- tetra- chlorethanol is mixed with 6: 4 weight ratio Reagent in, and spend 90 minutes dissolution wherein, thereafter, be transferred in Uberode viscosimeter, tieed up in 30 DEG C of constant temperature bath It holds 10 minutes, then obtains the whereabouts number of seconds of solution using viscosimeter and aspirator.The whereabouts of solvent is obtained in an identical manner After number of seconds, R.V. and I.V. value is calculated with following equation 1 and 2.

[equation 1]

[equation 2]

Wherein, C indicates the concentration of sample.

3) oligomer (%)

Chloroform is added in sample solvent HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) with oligomer quantitative manner, It dissolves at room temperature, then, acetonitrile precipitation is polymer.Thereafter, standard substance (cyclic oligomer) is obtained using LC analytical equipment Calibration curve, the purity of cyclic oligomer is then determined by sample analysis.As analytical equipment, use LC (liquid chromatogram) With 1100 series of Agilent.

4) DEG (diethylene glycol (DEG)) content (%)

Following measurement DEG content: 1g sample is added into 50ml container, 3ml monoethanolamine is then added, uses heating plate It is heated to be completely dissolved sample, solution is then cooled to 100 DEG C, be added in 20ml methanol and be dissolved with the 1,6- of 0.005g 10g terephthalic acid (TPA) is added to neutralize the solution in the solution of hexylene glycol.After filtering thus obtained neutralization using funnel and filter paper Solution, then by the DEG content (wt%) of gas chromatographic measurement filtrate.GC points are carried out using the GC analyzer of Shimadzu Analysis, measures according to Shimadzu GC handbook.

5) mist degree

Film is measured according to JIS K 715 using mist degree instrument (model name: Nipon denshoku, Model NDH 5000) The mist degree of form sample.

6) haze change rate (Δ H)

In order to measure the surface migration of oligomer in film, film is placed on the top having a size of 3cm high, 21cm wide and 27cm long In the chest of portion's opening, carry out being heat-treated for 60 minutes at 150 DEG C then keeping 5 points to make oligomer migration to the surface of film Clock reuses mist degree instrument (Nipon denshoku, Model NDH 5000) according to JIS K 715 and measures haze value.

Haze change rate is calculated according to following formula 11:

Δ H (%)=Hf-Hi [formula 11]

Wherein, Hf indicates that the mist degree that 60 minutes caudacorias are maintained at 150 DEG C, Hi indicate the mist degree of film before heating.

7) the dry coating thickness of priming coat

In the overall with for the basilar memebrane for being coated with coating composition, referred to being spaced on longitudinal vertical direction (TD) for 1m Fixed 5 points, measure the part of film using SEM (Hitachi S-4300), with 50,000 × enlargement ratio to this 30 points in interval measure to calculate average value.

8) surface roughness (Ra)

Use equipment: 3 dimensions non-planar contact surfaces roughness test instrument (NT 2000, WYCO)

Use device measuring Ra (center line average roughness) above

9) surface orientation coefficient

It longitudinally, laterally with the refractive index on thickness direction, and is being calculated as follows using Abbe refractometer (ATOGO) measurement Surface orientation coefficient:

Surface orientation coefficient (ns)={ (refractive index in the longitudinal direction+refractive index) horizontally/2 }-are { (in the longitudinal direction The refractive index of the thickness of the refractive index of thickness+horizontally)/2.

10) measurement of swelling ratio, gel fraction and Tg

It is 80mm and a height of that diameter, which is added, in the water dispersed resin composition that 15g is prepared in embodiment and comparative example It is 24 hours dry at 80 DEG C in the circle bowl of the size of 15mm, it is 3 hours dry at 120 DEG C, and aging 1 is small at 180 DEG C When.After coated film after being taken out 1g drying, Tg is measured.In addition, the coated film after drying is immersed in 50g distilled water Later, it is placed 24 hours at 70 DEG C.The coated film being taken out after placing, for measuring swelling ratio.By the painting after holding After cloth film is 3 hours dry at 120 DEG C, its weight is recorded to measure gel fraction.

(1) swelling ratio

Coated film of the about 1g after dry is immersed in 50g distilled water, is placed 24 hours at 70 DEG C, is taken out placement Coated film afterwards records its weight.

Swelling ratio=(weight-initial weight after placement)/initial weight × 100

(2) gel fraction

Its weight is dried 3 hours at 120 DEG C and recorded to coated film after placement.

Gel fraction=(weight/initial weight after dry) × 100

(3) Tg is measured

Tg is measured using DSC equipment (Perkin Elmer DSC 7) with two wheel modes.With Perkin Elmer DSC 7 It is measured using coated film of the 10-11mg after dry.

The first round=0-200 DEG C of raising temperature, rate are 200 DEG C/min,

By temperature maintain 200 DEG C of retention times be 3 minutes, then

=200--40 DEG C of cooling, rate are 200 DEG C/min,

By temperature maintain -40 DEG C of retention times be 5 minutes.

Second take turns=is measured under conditions of -40-200 DEG C with the rate of 20 DEG C/min.

11) generation crimped

By after hard coating process film and film to be evaluated be laminated at 150 DEG C with the rate of 3mpm, will lamination system Product are cut into A4 dimensional standard (29.7cm wide and 21.0cm long) on TD.Then, it measures and is placed in the hot wind for maintaining 80 DEG C Change in size in baking oven after 12 hours.Measure the variation of each dimension of the height from the bottom of A4 film to 4 edges.

Determine whether to crimp by the height from the bottom of film to edge: when height is 3mm or less, determine not It crimps.

Adhesive resin used in the following examples and comparative example is as follows:

1) KLX-007 adhesive

(A) acrylic compounds formed and being copolymerized the unsaturated monomer of the free redical polymerization containing glycidyl Solid content weight ratio between resin, with (B) water dispersible polyester resinoid is (A)/(B)=50/50, wherein acrylic compounds Resin includes the unsaturated monomer of the free redical polymerization containing glycidyl of the 50mol% of whole monomer components, as Comonomer, the diethylene glycol (DEG) of 50mol% of the water dispersible polyester resinoid comprising whole diol components, and whole acid constituents The sulfonate alkali metal salt compound of 10mol%.

2) P3208 adhesive

The product of Rohm&Haas, the methyl methacrylate comprising 40wt%, 40wt% weight ethyl acrylate and The melamine of 20wt%.

[embodiment 1]

1) preparation of water dispersed resin composition (1)

The propylene of use (A) formation and being copolymerized the unsaturated monomer of the free redical polymerization containing glycidyl The adhesive conduct that solid content weight ratio between acid resin and (B) water dispersible polyester resinoid is (A)/(B)=40/60 Adhesive.

(A) acrylic resin is the vinyl propionate by the glycidyl acrylate and 40mol% that make 60mol% The resin of copolymerization and formation, weight average molecular weight 35000.

(B) water dispersible polyester resinoid is the diol component (diethylene glycol (DEG) and 50mol% of 50mol% relative to 50mol% Ethylene glycol) use 50mol% acid constituents (the sulfonic group terephthalic acid (TPA) of 15mol% and the terephthalic acid (TPA) of 85mol%) Resin made of copolymerization, weight average molecular weight 14000.

By the organic silicon wetting agent (BYK of BYK CHEMIE of adhesive and 0.3wt% that solid content is 0.5wt% 348) it is added to the water, stirs 2 hours, to prepares the water dispersed resin composition (1) that total solids content is 0.8wt%.

Swelling ratio, gel fraction and Tg as described above are measured using the water dispersed resin composition thus prepared, as a result It indicates in following table 1.

2) preparation of the polyester film of oligomer retardance

It is 0.65 by inherent viscosity as basal layer (B), diethylene glycol content 1.2wt%, oligomer is Extruder is added with melting extrusion in the polyethylene terephthalate of 1.4wt%, as surface layer (A), using passing through solid polycondensation Preparation, inherent viscosity 0.67 are closed, diethylene glycol content is 0.8wt% and oligomer is the poly- to benzene two of 0.5wt% Formic acid glycol ester thin slice, and the diameter of the 50ppm relative to total polyethylene terephthalate weight is 0.7 μm Silicon dioxide granule, so that preparation is cast into 3 layers of A/B/A of thin slice extrudate.Thereafter, it will thus be made by stick coating method Standby water dispersed resin composition (1) coating on both surfaces, then with 1 DEG C it is per second raise the temperature to 110-150 DEG C, After preheating and drying, stretched on TD with 3.5 times of ratio.Thereafter, hot place is carried out at 230 DEG C in 5 column stenters Reason, the relaxation 10% on MD and TD at 200 DEG C, and thermal finalization is carried out, to have cated 188 on two surfaces of preparation μm biaxial stretching film.

Thus the Polyester multilayer membrane prepared have the 80wt% of total film weight basal layer and total film weight The surface layer of 20wt%, and the dry coating of the priming coat of composition is with a thickness of 20nm.The physical property table of obtained polyester film Show in following table 2.

[embodiment 2]

1) preparation of water dispersed resin composition (2)

The propylene of use (A) formation and being copolymerized the unsaturated monomer of the free redical polymerization containing glycidyl The adhesive conduct that solid content weight ratio between acid resin and (B) water dispersible polyester resinoid is (A)/(B)=70/30 Adhesive.

(A) acrylic resin be 60mol% glycidyl acrylate and 40mol% vinyl propionate copolymerization and The resin of formation, weight average molecular weight 30000.

(B) water dispersible polyester resinoid is the diol component (diethylene glycol (DEG) and 50mol% of 50mol% relative to 50mol% Ethylene glycol) use 50mol% acid constituents (the sulfonic group terephthalic acid (TPA) of 15mol% and the terephthalic acid (TPA) of 85mol%) The resin of copolymerization and formation, weight average molecular weight 12000.

By the organic silicon wetting agent (BYK of BYK CHEMIE of adhesive and 0.3wt% that solid content is 5wt% 348) it is added to the water, stirs 2 hours, to prepares the water dispersed resin composition (2) that total solids content is 5.3wt%.It uses Thus the water dispersed resin composition prepared measures swelling ratio, gel fraction and Tg as described above, as a result indicates following In table 1.

Being prepared on two surfaces in the same manner as example 1 using the water dispersed resin composition (2) of preparation is had 188 μm of biaxial stretching film of coating.The dry coating of the priming coat of composition is with a thickness of 110nm.The object of obtained polyester film Rationality matter indicates in following table 2.

[embodiment 3]

It is 0.65 by inherent viscosity as basal layer (B), diethylene glycol content 1.2wt%, oligomer is Extruder is added with melting extrusion in the polyethylene terephthalate of 1.4wt%, as surface layer (A), using passing through solid polycondensation Preparation, inherent viscosity 0.67 are closed, diethylene glycol content is 0.7wt% and oligomer is the poly- to benzene two of 0.5wt% Formic acid glycol ester thin slice, and the diameter of the 50ppm relative to total polyethylene terephthalate weight is 0.7 μm Silicon dioxide granule, so that preparation is cast into 3 layers of A/B/A of thin slice extrudate.Thereafter, it will thus be made by stick coating method Standby water dispersed resin composition (1) coating on both surfaces, then with 1 DEG C it is per second raise the temperature to 110-150 DEG C, After preheating and drying, stretched on TD with 3.5 times of ratio.Thereafter, hot place is carried out at 230 DEG C in 5 column stenters Reason, the relaxation 10% on MD and TD at 200 DEG C, and thermal finalization is carried out, to have cated 188 on two surfaces of preparation μm biaxial stretching film.

Thus the Polyester multilayer membrane prepared have the 80wt% of total film weight basal layer and total film weight The surface layer of 20wt%, the dry coating of the priming coat of composition is with a thickness of 20nm.The physical property of obtained polyester film indicates In following table 2.

[embodiment 4]

It is 0.65 by inherent viscosity as basal layer (B), diethylene glycol content 1.2wt%, oligomer is Extruder is added with melting extrusion in the polyethylene terephthalate of 1.4wt%, as surface layer (A), using passing through solid polycondensation Preparation, inherent viscosity 0.67 are closed, diethylene glycol content is 0.7wt% and oligomer is the poly- to benzene two of 0.5wt% Formic acid glycol ester thin slice, and the diameter of the 50ppm relative to total polyethylene terephthalate weight is 0.7 μm Silicon dioxide granule, so that preparation is cast into 3 layers of A/B/A of thin slice extrudate.Thereafter, it will thus be made by stick coating method Standby water dispersed resin composition (2) coating on both surfaces, then with 1 DEG C it is per second raise the temperature to 110-150 DEG C, After preheating and drying, stretched on TD with 3.5 times of ratio.Thereafter, hot place is carried out at 230 DEG C in 5 column stenters Reason, the relaxation 10% on MD and TD at 200 DEG C, and thermal finalization is carried out, to have cated 188 on two surfaces of preparation μm biaxial stretching film.

Thus the Polyester multilayer membrane prepared have the 80wt% of total film weight basal layer and total film weight The surface layer of 20wt%, the dry coating of the priming coat of composition is with a thickness of 110nm.The physical property of obtained polyester film indicates In following table 2.

[embodiment 5]

It is 0.65 by inherent viscosity as basal layer (B), diethylene glycol content 1.2wt%, oligomer is Extruder is added with melting extrusion in the polyethylene terephthalate of 1.4wt%, as surface layer (A), using passing through solid polycondensation Preparation, inherent viscosity 0.67 are closed, diethylene glycol content is 0.8wt% and oligomer is the poly- to benzene two of 0.4wt% Formic acid glycol ester thin slice, and the diameter of the 50ppm relative to total polyethylene terephthalate weight is 0.7 μm Silicon dioxide granule, so that preparation is cast into 3 layers of A/B/A of thin slice extrudate.Thereafter, it will thus be made by stick coating method Standby water dispersed resin composition (1) coating on both surfaces, then with 1 DEG C it is per second raise the temperature to 110-150 DEG C, After preheating and drying, stretched on TD with 3.5 times of ratio.Thereafter, hot place is carried out at 230 DEG C in 5 column stenters Reason, the relaxation 10% on MD and TD at 200 DEG C, and thermal finalization is carried out, to have cated 188 on two surfaces of preparation μm biaxial stretching film.

[embodiment 6]

It is 0.65 by inherent viscosity as basal layer (B), diethylene glycol content 1.2wt%, oligomer is Extruder is added with melting extrusion in the polyethylene terephthalate of 1.4wt%, as surface layer (A), using passing through solid polycondensation Preparation, inherent viscosity 0.67 are closed, diethylene glycol content is 0.8wt% and oligomer is the poly- to benzene two of 0.4wt% Formic acid glycol ester thin slice, and the diameter of the 50ppm relative to total polyethylene terephthalate weight is 0.7 μm Silicon dioxide granule, so that preparation is cast into 3 layers of A/B/A of thin slice extrudate.Thereafter, it will thus be made by stick coating method Standby water dispersed resin composition (2) coating on both surfaces, then with 1 DEG C it is per second raise the temperature to 110-150 DEG C, After preheating and drying, stretched on TD with 3.5 times of ratio.Thereafter, hot place is carried out at 230 DEG C in 5 column stenters Reason, the relaxation 10% on MD and TD at 200 DEG C, and thermal finalization is carried out, to have cated 188 on two surfaces of preparation μm biaxial stretching film.

[embodiment 7]

Thus the Polyester multilayer membrane prepared have the 70wt% of total film weight basal layer and total film weight The surface layer of 30wt%, the dry coating of the priming coat of composition is with a thickness of 20nm.The physical property of obtained polyester film indicates In following table 2.

[embodiment 8]

It is 0.65 by inherent viscosity as basal layer (B), diethylene glycol content 1.2wt%, oligomer is Extruder is added with melting extrusion in the polyethylene terephthalate of 1.4wt%, as surface layer (A), using passing through solid polycondensation Preparation, inherent viscosity 0.67 are closed, diethylene glycol content is 0.8wt% and oligomer is the poly- to benzene two of 0.5wt% Formic acid glycol ester thin slice, and the diameter of the 50ppm relative to total polyethylene terephthalate weight is 0.7 μm Silicon dioxide granule, so that preparation is cast into 3 layers of A/B/A of thin slice extrudate.Thereafter, it will thus be made by stick coating method Standby water dispersed resin composition (2) coating on both surfaces, then with 1 DEG C it is per second raise the temperature to 110-150 DEG C, After preheating and drying, stretched on TD with 3.5 times of ratio.Thereafter, hot place is carried out at 230 DEG C in 5 column stenters Reason, the relaxation 10% on MD and TD at 200 DEG C, and thermal finalization is carried out, to have cated 188 on two surfaces of preparation μm biaxial stretching film.

Thus the Polyester multilayer membrane prepared have the 70wt% of total film weight basal layer and total film weight The surface layer of 30wt%, and the dry coating of the priming coat of composition is with a thickness of 110nm.The physical property table of obtained polyester film Show in following table 2.

[comparative example 1]

It is 0.65 by inherent viscosity as basal layer (B), diethylene glycol content 1.2wt%, oligomer is Extruder is added with melting extrusion in the polyethylene terephthalate of 1.4wt%, as surface layer (A), using passing through solid polycondensation Preparation, inherent viscosity 0.67 are closed, diethylene glycol content is 0.8wt% and oligomer is the poly- to benzene two of 0.5wt% Formic acid glycol ester thin slice, and the diameter of the 50ppm relative to total polyethylene terephthalate weight is 0.7 μm Silicon dioxide granule, so that preparation is cast into 3 layers of A/B/A of thin slice extrudate.Thereafter, it per second is raised the temperature to 1 DEG C It 110-150 DEG C, after preheating and drying, is stretched on TD with 3.5 times of ratio.Thereafter, 230 in 5 column stenters It is heat-treated at DEG C, the relaxation 10% on MD and TD at 200 DEG C, and carries out thermal finalization, thus on two surfaces of preparation Has cated 188 μm of biaxial stretching film.

The 20wt%'s of the substrate and total film weight of 80wt% of the Polyester multilayer membrane of preparation with total film weight Surface layer.The physical property of obtained polyester film indicates in following table 2.

[comparative example 2]

It is 0.65 by inherent viscosity as basal layer (B), diethylene glycol content 1.2wt%, oligomer is Extruder is added with melting extrusion in the polyethylene terephthalate of 1.4wt%, as surface layer (A), using passing through solid polycondensation Preparation, inherent viscosity 0.67 are closed, diethylene glycol content is 0.8wt% and oligomer is the poly- to benzene two of 1.4wt% Formic acid glycol ester thin slice, and the diameter of the 50ppm relative to total polyethylene terephthalate weight is 0.7 μm Silicon dioxide granule, so that preparation is cast into 3 layers of A/B/A of thin slice extrudate.Thereafter, it will thus be made by stick coating method Standby water dispersed resin composition (1) coating on both surfaces, then with 1 DEG C it is per second raise the temperature to 110-150 DEG C, After preheating and drying, stretched on TD with 3.5 times of ratio.Thereafter, hot place is carried out at 230 DEG C in 5 column stenters Reason, the relaxation 10% on MD and TD at 200 DEG C, and thermal finalization is carried out, to have cated 188 on two surfaces of preparation μm biaxial stretching film.

[comparative example 3]

Using the adhesive of the product for Rohm&Haas, the propylene of methyl methacrylate, 40wt% comprising 40wt% The melamine of acetoacetic ester and 20wt%.

By the organic silicon wetting agent (BYK of BYK CHEMIE of adhesive and 0.3wt% that solid content is 2wt% 348) it is added to the water, stirs 2 hours, to prepares the water dispersed resin composition (3) that total solids content is 2.3wt%.It uses Thus the water dispersed resin composition prepared measures swelling ratio, gel fraction and Tg as described above, as a result indicates following In table 1.

Being prepared on two surfaces in the same manner as example 1 using the water dispersed resin composition (3) of preparation is had 188 μm of biaxial stretching film of coating.The dry coating of the priming coat of composition is with a thickness of 80nm.The physics of obtained polyester film Property indicates in following table 2.

[comparative example 4]

The aqueous polyurethane adhesive that solid content is 20wt% is prepared, by the polyester polyol (weight for making 9wt% The polyethylene adipate diol (polyethylene adipatediol) that average molecular weight is 1000), the hexa-methylene of 10wt% Reactive emulsifier (Asahi Denka, Adekaria Soap SETM, the alkene with ion radical of diisocyanate, 1wt% Sulphonic acid ester (the sulfonic acid ester of of propylglycidyl base nonylphenyl polyoxyethylene ether Polyoxyethylene allyl glycidyl nonylphenyl ether)) and the water of 80wt% reacted and carry out shape At.

By the organic silicon wetting agent (BYK of BYK CHEMIE of adhesive and 0.3wt% that solid content is 4wt% 348) it is added to the water, stirs 2 hours, to prepares the water dispersed resin composition (4) that total solids content is 4.3wt%.It uses Thus the water dispersed resin composition prepared measures swelling ratio, gel fraction and Tg as described above, as a result indicates following In table 1.

Being prepared on two surfaces in the same manner as example 1 using the water dispersed resin composition (4) of preparation is had 188 μm of biaxial stretching film of coating.The dry coating of the priming coat of composition is with a thickness of 80nm.The physics of obtained polyester film Property indicates in following table 2.

[comparative example 5]

In the case where solvent is not present by 40mol (26mol%) 2,6- naphthalene dicarboxylic acids, 5mol (3.3mol%) 2,5- bis- The ethylene glycol of carboxylic acid benzene sulfonic acid sodium salt, 5mol (3.3mol%) dimethyl terephthalic acid and 100mol (66.66mol%) with 1: 1 mixture of 1,4-butanediol is mixed, and is put into reactor, by being per minute increased to temperature from 170 DEG C with 1 DEG C 250 DEG C are reacted, to carry out emulsion reaction while remove the water or methanol as by-product, temperature is increased to 260 DEG C, simultaneously Pressure in reactor is down to 1mmHg, so that carrying out polycondensation reaction is collected simultaneously glycol for by-product, thus prepares characteristic The polyester resin that viscosity is 0.4.

The water of 75wt% is added in the polyester resin of 25wt% thus prepared, and is emulsified to prepare 25wt%'s Waterborne polyester adhesive.

By the organic silicon wetting agent (BYK of BYK CHEMIE of adhesive and 0.3wt% that solid content is 4wt% 348) it is added to the water, stirs 2 hours, to prepares the water dispersed resin composition (5) that total solids content is 4.3wt%.It uses Thus the water dispersed resin composition prepared measures swelling ratio, gel fraction and Tg as described above, as a result indicates following In table 1.

Being prepared on two surfaces in the same manner as example 1 using the water dispersed resin composition (5) of preparation is had 188 μm of biaxial stretching film of coating.The dry coating of the priming coat of composition is with a thickness of 70nm.The physics of obtained polyester film Property indicates in following table 2.

[table 1]

[table 2]

As shown in table 1 above and 2, it can be seen that Polyester multilayer membrane according to the present invention is before and after the heat treatment With low haze change rate, to show the characteristic for being suitable as optical film.

However, find out from comparative example 1, in the case where not carrying out priming coat process, the only polymeric sheet of basement membrane Improve, haze change rate is high, and big weight oligomers occurs in post-processing with other film layer pressures during, to be unsatisfactory for Physical property of the invention.In addition, from comparative example 2 it was determined that film is super when the oligomer on surface layer is 1.4% Out for the required physical property range of mist degree.From comparative example 3,4 and 5 as can be seen that haze change rate is with primary coat Layer composition and change.

[embodiment 9]

1) preparation of water dispersed resin composition (6)

By the KLX-007 adhesive (water-dispersed composition that solid content is 25%) of 16wt%, the organosilicon of 0.3wt% The average grain diameter of class wetting agent (Dow Corning, polyester siloxane copolymer, Q2-5212) and 0.3wt% are 140nm's Colloidal silica particles are added to the water, and stir 2 hours, to prepare the water dispersed resin group that total solids content is 4.6wt% It closes object (6).

2) preparation of the oligomer retardance polyester film with controllable percent thermal shrinkage

The polyethylene terephthalate thin slice for removing water is added in extruder, from wherein melting extrusion, and is utilized The curtain coating drum that surface temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Ester piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is then cooled down To room temperature.Thereafter, on both surfaces, then the water dispersed resin composition (6) thus prepared is coated with by stick rubbing method By temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio. Thereafter, it is heat-treated at 235 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD pine The relaxation rate of relaxation equipment is adjusted to 1.25%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

The dry coating of the priming coat of composition is with a thickness of 80nm.The physical property of thus obtained polyester film indicates under In the table 3 and 4 in face.

[embodiment 10]

1) preparation of water dispersed resin composition (7)

By the KLX-007 adhesive (water-dispersed composition that solid content is 25%) of 8wt%, the organosilicon of 0.3wt% The average grain diameter of class wetting agent (Dow Corning, polyester siloxane copolymer, Q2-5212) and 0.3wt% are 140nm's Colloidal silica particles are added to the water, and stir 2 hours, to prepare the water dispersed resin group that total solids content is 2.6wt% It closes object (7).

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (7) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 235 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 1.25%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

The dry coating of the priming coat of composition is with a thickness of 40nm.The physical property of thus obtained polyester film indicates under In the table 3 and 4 in face.

[embodiment 11]

1) preparation of water dispersed resin composition (8)

By the KLX-007 adhesive (water-dispersed composition that solid content is 25%) of 24wt%, the organosilicon of 0.3wt% The average grain diameter of class wetting agent (Dow Corning, polyester siloxane copolymer, Q2-5212) and 0.3wt% are 140nm's Colloidal silica particles are added to the water, and stir 2 hours, to prepare the water dispersed resin group that total solids content is 6.6wt% It closes object (8).

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (8) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 235 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 1.25%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

The dry coating of the priming coat of composition is with a thickness of 160nm.The physical property of thus obtained polyester film indicates In following table 3 and 4.

[embodiment 12]

1) preparation of the oligomer retardance polyester film with controllable percent thermal shrinkage

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (6) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 245 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 1.25%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

[embodiment 13]

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (6) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 237 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 2.0%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

[embodiment 14]

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (6) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 244 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 2.0%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

[comparative example 6]

1) preparation of water dispersed resin composition (9)

By the P-3208 adhesive (water-dispersed composition that solid content is 44%) of 9.1wt%, the organosilicon of 0.3wt% The average grain diameter of class wetting agent (Dow Corning, polyester siloxane copolymer, Q2-5212) and 0.3wt% are 140nm's Colloidal silica particles are added to the water, and stir 2 hours, to prepare the water dispersed resin group that total solids content is 4.6wt% It closes object (9).

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (9) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 235 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 1.25%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

[comparative example 7]

1) preparation of the oligomer retardance polyester film with uncontrollable percent thermal shrinkage

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (6) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 235 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 1.00%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

[comparative example 8]

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (6) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 235 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 3.00%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

[comparative example 9]

Extruder is added in the polyethylene terephthalate thin slice for removing water, from wherein melting extrusion, and utilizes table The curtain coating drum that face temperature is 20 DEG C is quenched and is solidified, thus polyethylene terephthalate of the preparation with a thickness of 1500 μm Piece.The polyethylene terephthalate piece of preparation is stretched on MD at 80 DEG C with 3.5 times of ratio, is subsequently cooled to Room temperature.Thereafter, the water dispersed resin composition (6) thus prepared is coated on both surfaces by stick rubbing method, then will Temperature with 1 DEG C it is per second be increased to 110-150 DEG C, after preheating and drying, stretched on TD with 3.5 times of ratio.Its Afterwards, it is heat-treated at 235 DEG C in 5 column stenters, the relaxation 10% on TD at 200 DEG C carries out thermal finalization, MD relaxation The relaxation rate of equipment is adjusted to 0%, to have cated 125 μm of biaxial stretching film on two surfaces of preparation.

[table 3]

[table 4] MD/TD percent thermal shrinkage (%)

[table 5] diagonal line percent thermal shrinkage (%)

As shown in table 3 above, it can be seen that polyester film according to the present invention has low before and after the heat treatment Haze change rate, to show the excellent characteristics as optical film.However, by comparative example 6 it was determined that haze change Rate changes with the composition of priming coat.I.e., it is possible to determine, the choosing of the difference of oligomer retardation capability degree because of the composition of coating It selects.

It, can be with by the heat treatment temperature and relaxation rate on MD (MD relaxation rate) in addition, as shown in table 4 above Uniformly ensure the percent thermal shrinkage of target on the basis of overall with.This determines that the curling problem of product can be controlled.However, by right Than embodiment 7 as can be seen that needed for being only difficult to ensure that percent thermal shrinkage reaches with traditional equipment when using 1.0% MD relaxation rate Level, and uniformity also reduces.In addition, film cannot be formed in comparative example 8 when MD relaxation rate is set as 3.0%.

Although by comparative example 9 it was determined that MD percent thermal shrinkage is preferable, the percent thermal shrinkage deviation between MD and TD is In the case where 0.2%, but the curling of 3.5mm occurs, there are problems for this.In this case, the shape of the curling of generation is Curling only occurs in the distorted shape (distortion curling) on both sides diagonally adjacent in four edges, this is received by diagonal line heat Caused by the difference of shrinkage.As shown in table 3, it may be determined that the difference of diagonal line percent thermal shrinkage is by the item of formation membrane process Caused by the difference of part, and this species diversity causes to distort curling in laminating technology.That is, in the feelings of comparative example 9 Under condition, it may be determined that although the percent thermal shrinkage deviation on MD and TD is preferable within the scope of the overall with of film, diagonal line heat is received The difference of shrinkage is uneven, therefore, is able to carry out curl control in the central part without very big difference, but has The two side portions of 0.2% or more difference cannot be crimped control, and be distorted curling.

[embodiment 15]

It respectively, the use of inherent viscosity is 0.65 in basal layer, diethylene glycol (DEG) (DEG) content is 1.2%, oligomer For 1.4% PET thin slice, it is 0.67 that the inherent viscosity of solid phase is used in surface layer, DEG content 0.8wt%, oligomer The PET thin slice that content is 0.5%, and coextrusion casting is carried out using the particle that the partial size of 30ppm is 0.7 μm.Thereafter, with 3.2 times and 3.2 times of ratio is successively stretched on MD and TD, and is heat-treated at 230 DEG C, is applied on TD 3% relaxation prepares 125 μm of multilayer film.Herein, in maximum width length after the stretch, the relaxation on TD is successively mentioned For three sections of relaxation of the thermal treatment zone in stenter, however, width x length reduces 3% length on maximum width direction Degree.

Herein, during the particle composition on surface layer and content are shown in Table 6 below.

The 80% of the basal layer Zhan of multilayer film total film weight, the 20% of surface layer Zhan total film weight, thus in the system of film After standby, oligomer surface migration, surface roughness, mist degree, surface orientation coefficient and the shrinking percentage of film are measured.

[embodiment 16 and 17]

As shown in Table 6 below, only other than the DEG content of the raw material on surface layer, in a manner of identical with embodiment 15 Carry out the process.

Measure oligomer surface migration, surface roughness, mist degree, surface orientation coefficient and the shrinking percentage of obtained film.

[embodiment 18 and 19]

As shown in Table 6 below, only other than the oligomer of the raw material on surface layer, with side identical with embodiment 15 Formula carries out the process.

[embodiment 20 and 21]

Other than the weight on surface layer such as following table 6, the process is carried out in a manner of identical with embodiment 15.

[embodiment 22 and 23]

Other than the particle content on surface layer such as following table 6, the process is carried out in a manner of identical with embodiment 15.

[embodiment 24]

Other than applying 1.5% relaxation while relaxation on TD on MD, with identical with embodiment 15 Mode carries out the process.

[comparative example 10]

In addition to the inherent viscosity on surface layer is 0.65, and the PET that oligomer is 1.4% is used alone, and only Other than in the particle such as embodiment 16 on surface layer, the process is carried out in a manner of identical with embodiment 15.After preparing film, measurement Its oligomer surface migration, surface roughness, mist degree, surface orientation coefficient and shrinking percentage.

[comparative example 11 and 12]

Other than the DEG content on surface layer is as described in table 6, the process is carried out in a manner of identical with embodiment 15.

[comparative example 13 and 14]

Other than the oligomer on surface layer is as described in table 6, the process is carried out in a manner of identical with embodiment 15. Measure oligomer surface migration, surface roughness, mist degree, surface orientation coefficient and the shrinking percentage of obtained film.

[comparative example 15 and 16]

[comparative example 17 and 18]

[comparative example 19 and 20]

In addition to forming film under 200 DEG C and 210 DEG C of heat treatment temperature, and the relaxation on TD is 1% and 1.5% In addition, the process is carried out in a manner of identical with embodiment 16.

[table 6]

^*Co-extrusion is A/B/A.(skin depth is two A layers of total amount)

[table 7]

As shown in table 7 above, in an embodiment of the present invention it was determined that film has maintains 30 points at 150 DEG C Lower percent thermal shrinkage after clock in the range of meeting formula 1 and 2, surface orientation coefficient are 0.1590 or more, rough surface Mist degree of the mist degree (Hi) less than 1.5%, after film is maintained 30 minutes at 150 DEG C hereinafter, before heating film is spent for 10nm All meet formula 9.

It is above, preferred illustrative embodiment of the invention is described, however, various changes can be used in the present invention Type and equivalent, and it is readily apparent that above embodiment can suitably modification and be applied in the same manner.Therefore, on The description in face does not limit the scope of the present invention being defined by the claims appended hereto.

Claims

1. a kind of polyester film, comprising:

Polyester base film, and

Priming coat is formed by being coated with water dispersed resin composition on one or two surface of the polyester base film,

Wherein, the polyester base film includes: basal layer, and at least two tables being laminated on two surfaces of the basal layer Layer, the oligomer for forming the polyester resin on the surface layer is 0.3wt%-0.6wt%, diethylene glycol content 0.1wt%- 1.2wt%,

The water dispersed resin composition includes to be passed through to keep the unsaturation of the free redical polymerization containing glycidyl single by (A) The acrylic resin and (B) water dispersible polyester resinoid that body is copolymerized and is formed are formed by adhesive resin,

(A) acrylic compounds formed and the unsaturated monomer by making the free redical polymerization containing glycidyl is copolymerized Solid content weight ratio between resin and (B) described water dispersible polyester resinoid is (A)/(B)=20-80/80-20,

The Tg of the priming coat is 60 DEG C or more, and swelling ratio is 30% hereinafter, gel fraction is 95% or more, density 1.3- 1.4, and

The dry coating of the priming coat is with a thickness of 20-150nm.

2. polyester film according to claim 1, wherein the polyester film meets following formula 1 to 4:

0≤Smd≤1.5 [formula 1]

0≤Std≤1.0 [formula 2]

Wherein, root after Smd and Std expression maintains the polyester film having a size of 10cm wide and 10cm long 30 minutes at 150 DEG C According to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement, wherein percent thermal shrinkage (%)=(length of film before the heat treatment The length of 30 minutes caudacorias spend-is maintained at 150 DEG C)/before the heat treatment film length × 100, Smd indicate film in longitudinal direction (MD) shrinking percentage (%) on, Std indicate shrinking percentage (%) of the film on transverse direction (TD),

- 0.2≤Vmd≤0.2 [formula 3]

- 0.2≤Vtd≤0.2 [formula 4]

Wherein, root after Vmd and Vtd expression maintains the polyester film having a size of 10cm wide and 10cm long 30 minutes at 150 DEG C According to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement, wherein percent thermal shrinkage (%)=(length of film before the heat treatment The length of 30 minutes caudacorias spend-is maintained at 150 DEG C) length × 100 of/film before the heat treatment；

Vmd indicates the overall with based on film, with the deviation of the percent thermal shrinkage of 10 samples of the interval selection of 50cm in the longitudinal direction (%)；And

Vtd indicates the overall with based on film, with the deviation of the percent thermal shrinkage of 10 samples of the interval selection of 50cm horizontally (%).

3. polyester film according to claim 1, wherein the polyester film meets following formula 5 to 7:

0≤S (45)≤1.0 [formula 5]

0≤S (135)≤1.0 [formula 6]

│ S (135)-S (45) │≤0.2 [formula 7]

Wherein, S (45) and S (135) expression the polyester film having a size of 10cm wide and 10cm long is maintained at 150 DEG C 30 minutes it Afterwards according to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement, wherein percent thermal shrinkage (%)=(film before the heat treatment Length-maintained at 150 DEG C 30 minutes caudacoria length)/film before the heat treatment length × 100；

S (45) indicates the diagonally adjacent shrinking percentage (%) on the 45° angle degree clockwise of the transverse direction (TD) based on film；

S (135) indicates the diagonally adjacent shrinking percentage (%) in 135 ° of angles clockwise of the transverse direction (TD) based on film.

4. polyester film according to claim 1, wherein the polyester film meets following formula 8 and 9:

0.1590≤ns [formula 8]

Hf≤Hi × 2.5 [formula 9]

Wherein, ns is surface orientation coefficient, wherein ns={ (refractive index in the longitudinal direction+refractive index) horizontally/2 }-( The refractive index of the thickness of the refractive index of longitudinal thickness+horizontally)/2；

Hf indicate film maintained 30 minutes at 150 DEG C after mist degree；And

Hi indicates the mist degree of film before heating.

5. polyester film according to claim 1, wherein the polyester base film is total to by the basal layer and the surface layer It extrudes to be formed, and there is the inherent viscosity for meeting following formula 10:

1 Ns/Nc≤1.2 < [formula 10]

Wherein, Ns indicates to form the inherent viscosity of the polyester resin on the surface layer；And

Nc indicates to form the inherent viscosity of the polyester resin of the basal layer.

6. polyester film according to claim 1, wherein form the characteristic of the polyester resin of the basal layer of the polyester base film Viscosity is 0.5 to 1.0, and the inherent viscosity for forming the polyester resin on the surface layer of the polyester base film is 0.6 to 1.0.

7. polyester film according to claim 1, wherein the polyester film is according to the haze change rate of following formula 11 (Δ H) is 0.1% or less:

Δ H (%)=Hf-Hi [formula 11]

Wherein, the mist degree after Hf expression film maintains 60 minutes at 150 DEG C；Hi indicates the mist degree of film before heating.

8. polyester film according to claim 1, wherein the solid of the adhesive resin of the water dispersed resin composition contains Amount is 0.5wt%-10wt%.

9. polyester film according to claim 1, wherein the water dispersed resin composition also includes organic silicon wetting Agent.

10. polyester film according to claim 1, wherein the water dispersible polyester resinoid is by making containing azochlorosulfonate acid alkali gold Belong to the dicarboxylic acid component of salt compound, and the diol component containing diethylene glycol (DEG) is copolymerized to be formed.

11. polyester film according to claim 1, wherein the water dispersible polyester resinoid includes whole diol components The diethylene glycol (DEG) of 20mol%-80mol%.

12. polyester film according to claim 1, wherein the water dispersible polyester resinoid includes whole acid constituents The sulfonate alkali metal salt compound of 6mol%-20mol%.

13. polyester film according to claim 1, wherein the acrylic resin includes whole monomer components The unsaturated monomer of the free redical polymerization containing glycidyl of 20mol%-80mol%, as comonomer.

14. polyester film according to claim 1, wherein the polyester base film is polyethylene terephthalate film.

15. polyester film according to claim 1, wherein the polyester base film with a thickness of 25-250 μm.

16. polyester film according to claim 1, wherein the polyester base film has the substrate of 70wt%-90wt% The surface layer of layer and 10wt%-30wt%.

17. polyester film according to claim 1, wherein the surface roughness (Ra) of the polyester film is 10nm or less.

18. polyester film according to claim 1, wherein the surface layer includes 100ppm inorganic particulate below.

19. polyester film according to claim 18, wherein the average grain diameter of the inorganic particulate is less than 3 μm.

20. polyester film according to claim 18, wherein the inorganic particulate is selected from silica, zeolite and kaolinite Any one or two or more mixture in soil.

21. a kind of optical film has applying on polyester film described in any one being formed in claim 1 to 20 selected from hard The functional coating of any one or more in layer, adhesive layer, optical diffusion layer, ITO layer and printing layer.

22. a kind of method for preparing polyester film, comprising:

B) moisture of the coating with oligomer retardation capability on one or two surface of the polyester base film of the simple tension Resin combination is dissipated, to form priming coat；

D) thermal finalization is carried out to the film after the biaxial tension, to the film on MD in the range of meeting following formula 12 It relaxes:

1.1≤relaxation rate (%)≤2.5 [formula 12]

Wherein, the relaxation rate (%)=(in the movement of cephacoria of the movement speed-in relaxation processes section of relaxation processes section inner membrance Speed)/relaxation processes section cephacoria movement speed × 100,

The water dispersed resin composition includes to be passed through to keep the unsaturation of the free redical polymerization containing glycidyl single by (A) The acrylic resin and (B) water dispersible polyester resinoid that body is copolymerized and is formed are formed by adhesive resin, and (A) is described logical It is described to cross the acrylic resin and (B) for so that the unsaturated monomer of the free redical polymerization containing glycidyl is copolymerized and is formed Solid content weight ratio between water dispersible polyester resinoid is (A)/(B)=20-80/80-20,

The dry coating of the priming coat is with a thickness of 20-150nm.

23. according to the method for claim 22, wherein the relaxation in d) on MD is in the temperature for meeting following formula 13 It is carried out in range:

Draft temperature (DEG C)≤relaxation temperature (DEG C) < heat setting temperature (DEG C) [formula 13].

24. according to the method for claim 22, wherein the percent thermal shrinkage (%) of the polyester film meets following formula 1 To 4:

0≤Smd≤1.0 [formula 1]

0≤Std≤0.5 [formula 2]

- 0.2≤Vmd≤0.2 [formula 3]

- 0.2≤Vtd≤0.2 [formula 4]

Wherein, Smd, Std, Vmd and Vtd indicate the polyester film having a size of 10cm wide and 10cm long maintaining 30 points at 150 DEG C According to the percent thermal shrinkage (%) of the film of JIS C-2318 measurement after clock, wherein the percent thermal shrinkage (%)=(in heat treatment The length-of cephacoria maintains the length of 30 minutes caudacorias at 150 DEG C)/before the heat treatment film length × 100, Smd indicate Shrinking percentage (%) of the film on longitudinal direction (MD), Std indicate shrinking percentage (%) of the film on transverse direction (TD), and Vmd is indicated based on film Overall with, the deviation (%) of percent thermal shrinkage of 10 samples selected with the interval of 50cm on MD, Vtd are indicated based on the complete of film Width, the deviation (%) of percent thermal shrinkage of 10 samples selected with the interval of 50cm on TD.

25. according to the method for claim 22, wherein the polyester film meets following formula 5 to 7:

0≤S (45)≤1.0 [formula 5]

0≤S (135)≤1.0 [formula 6]

│ S (135)-S (45) │≤0.2 [formula 7]

S (45) indicates the diagonally adjacent shrinking percentage (%) on the 45° angle degree clockwise of the transverse direction (TD) based on film；And

26. according to the method for claim 22, wherein the polyester film is according to the haze change rate of following formula 11 (Δ H) is 0.1% or less:

Δ H (%)=Hf-Hi [formula 11]

Wherein, Hf indicates the mist degree that 60 minutes caudacorias are maintained at 150 DEG C；And

Hi indicates the mist degree of film before heating.